[Coco] composite / s-video to hdmi

[Gene Heskett]

On Monday 17 December 2012 08:42:45 Louis Ciotti did opine:

> > Don't forget John, that I am a broadcast engineer, who has been making
> 
> sure
> 
> > there was a picture there when you turned on the tv, from 1962 to
> > 2002, 40 years.
> > 
> > > --
> > > Coco mailing list
> > > Coco at maltedmedia.com
> > > http://five.pairlist.net/mailman/listinfo/coco
> 
>  Gene,
> 
> I wonder how much horse power you need in an FPGA to digitize the NTSC
> output from any coco and convert it to VGA.  I have a Spartan-3e baord I
> have been using in my "free" time to try and lean how to use/program
> FPGAs.

You would need to be able to do at least a 4 bit depth of A/D conversion 
every 90 nanoseconds to begin to be usable.  Then once a line buffer has 
been filled, read it back out at a 45 nanosecond rate twice.  This would be 
a 2 buffer setup where you interchange the 2 buffers at the end of each 
coco line, so you are writing to one, while reading the other at vga 
speeds.

Custom chips to do that may be available, I've not researched it.  Since a 
similar function is now needed/used in our lcd tv's, and the production 
quantities needed are there, I see no reason it shouldn't be a $7.33 chip 
today.  The full 8 bit A/D is probably routinely done today.
 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


Cheers, Gene
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